The present invention relates to a tube pump, and more particularly, the present invention relates to a tube pump which does not cause bending or folding of a tube used for delivering fluid when the tube pump is actuated, thereby preventing the tube from being ruptured.
In general, a tube pump performs a function of delivering fluid by continuously changing a volume inside a tube. While a variety of tube pumps are disclosed in the art, a typical example of such tube pumps will be described hereinafter.
FIG. 8 is a cross-sectional view illustrating the conventional tube pump.
The conventional tube pump includes a housing 100, a tube 200, and a rotating bracket 300. The housing 100 has a semi-circular surface 101 which constitutes an inner surface of the housing 100. The tube 200 has an outer surface which is brought into line contact with the semi-circular surface 101 of the housing 100. The tube 200 is formed with an inlet port 201 through which fluid is intaken into the tube 200 and an outlet port 202 through which fluid is discharged out of the tube 200. The rotating bracket 300 is disposed at a center of curvature of the semi-circular surface 101 of the housing 100 and is rotated along the same locus as the semi-circular surface 101. The rotating bracket 300 has a plurality of squeezing rollers 301 which are respectively mounted to corner portions of the rotating bracket 300 so as to sequentially squeeze the tube 200 against the semi-circular surface 101 of the housing 100.
A driving section 400 for rotating the rotating bracket 300 is mounted to a center portion of the rotating bracket 300.
Accordingly, in the case that the tube pump is to be operated, as the driving section 400 which is mounted to the center portion of the rotating bracket 300, is actuated, the plurality of squeezing rollers 301 which are respectively mounted to the corner portions of the rotating bracket 300, repeatedly and sequentially squeeze the tube 200 against the semi-circular surface 101 of the housing 100, whereby fluid which is intaken through the inlet port 201 into the tube 200, can be delivered toward the outlet port 202.
However, the conventional tube pump constructed as mentioned above suffers from defects in that, since the tube 200 is sequentially and repeatedly squeezed against the semi-circular surface 101 of the housing 100 by the plurality of squeezing rollers 301 thereby to compress the fluid inside the tube 200, if the tube pump is used for a lengthy period of time, the tube 200 can be ruptured.
Also, the conventional tube pump is encountered with a problem in that a costly tube which have sufficiently high flexibility and elasticity, must be used as the tube 200 so as to enable the tube 200 to be easily returned to its original shape.
Accordingly, the present invention has been made in an effort to solve the problems occurring in the related art, and an object of the present invention is to provide a tube pump which delivers fluid by repeatedly and continuously creating and obliterating fluid chambers inside a tube surrounding a fixed shaft in such a way as not to cause bending or folding of the tube while the tube pump is actuated, thereby preventing the tube from being ruptured.
Another object of the present invention is to provide a tube pump in which a tube is disposed in such a way as to define substantially a linear contour, thereby enabling an inexpensive tube having not so high flexibility and elasticity to be used.
Still another object of the present invention is to provide a tube pump wherein a fluid flowing cross-sectional area, that is, a cross-sectional area change at any point along a fixed shaft over and under which upper and lower fluid chambers are repeatedly created in a tube in a manner such that the upper and lower fluid chambers are partitioned from each other by the fixed shaft, is always held constant, thereby preventing pulsation from being generated.
In order to achieve the above objects, according to one aspect of the present invention, there is provided a tube pump comprising: a driving shaft having a plurality of eccentric cams which are mounted to the driving shaft in a manner such that positions of top dead centers of the eccentric cams are sequentially lowered and then raised along a fluid flowing direction, the plurality of eccentric cams being spaced apart one from another by a predetermined distance; a fixed shaft positioned parallel to the driving shaft; a tube having an inner diameter which is larger than a diameter of the fixed shaft and surrounding the fixed shaft; and a plurality of actuation rods formed, at upper portions thereof, with a plurality of cam inserting holes into which the plurality of eccentric cams are respectively inserted and, at lower portions thereof, with a plurality of tube inserting slots through which the tube is inserted, the plurality of actuation rods being repeatedly raised and lowered in such a way as to be interlocked with rotation of the plurality of eccentric cams.
According to another aspect of the present invention, an inner surface of each actuation rod which inner surface defines the tube inserting slot, comprises upper and lower semi-circular surface portions and a pair of plane surface portions which connect both ends of the upper and lower semi-circular surface portions, and the fixed shaft always forces portions of the tube inserted through the tube inserting slot, to be respectively brought into tight contact with the pair of plane surface portions of the inner surface of each actuation rod, whereby a space inside the tube is divided into upper and lower space parts by the fixed shaft.
According to another aspect of the present invention, a distance between centers of the driving shaft and the fixed shaft is determined to be the same as that between centers of the cam inserting hole and the tube inserting slot, and a distance between centers of the upper and lower semi-circular surface portions of the inner surface of each actuation rod is determined to be smaller than two times of an eccentric distance of each eccentric cam in consideration of a percentage of contraction or expansion of the tube.
According to another aspect of the present invention, a bearing is intervened between a circumferential outer surface of the eccentric cam and a circumferential inner surface of each actuation rod, which defines the cam inserting hole, to reduce friction therebetween.
According to another aspect of the present invention, the tube inserting slots of the actuation rods are formed as circular tube inserting holes, and a tube having a circumferential outer surface which possesses a circular cross-section and an inner surface which defines a slot, is inserted through the circular tube inserting holes of the actuation rods.
According to still another aspect of the present invention, the inner surface of the tube which inner surface defines the slot, comprises upper and lower semi-circular surface portions and a pair of plane surface portions which connect both ends of the upper and lower semi-circular surface portions, and the fixed shaft always forces portions of the tube inserted through the circular tube inserting holes of the actuation rods, to be respectively brought into tight contact with portions of each actuation rod, at the pair of plane surface portions, whereby a space inside the tube is divided into upper and lower space parts by the fixed shaft.
According to yet still another aspect of the present invention, each actuation rod has a cam mounting section and a tube mounting section which are connected with each other by a hinge member, the tube mounting section of each actuation rod is formed with a pair of plane surface portions, and a pair of vertical guides are disposed at sides of the plane surface portions of the actuation rods to enable the tube mounting sections of the actuation rods to be raised and lowered along a vertical direction.